SOUTH BEND, Ind. -- Skip Holtz returned to a place that educated and shaped him. As soon as he reached campus, his memories from Notre Dame jumped out.

And now he's created an even more vivid one. Holtz and the South Florida Bulls came to South Bend and upset the 16th-ranked Irish 23-20 Saturday in a wild game that was twice disrupted by heavy storms.

"I don't know if all that's hit me yet. Notre Dame's a special place," Holtz said. "And it was great to come back."

His dad, Lou Holtz, wasn't there Saturday. But there were plenty of family members there to see one of Skip Holtz's biggest wins.

Lou led Notre Dame to its last national title in 1988. Skip graduated from Notre Dame, played a year for his father and then coached with him in South Bend.

The weather wasn't cooperating for this homecoming.

Officials asked fans to leave the stadium at halftime because of severe weather, mostly lightning, and the teams then stayed in their locker rooms for 2 hours, 10 minutes until it cleared. South Florida led 16-0 at the time.

Then with 4:21 to play, the game was delayed for 43 minutes and again fans departed the stadium with wicked lightning flickering around the stadium.

Holtz praised his team's poise.

"To have the kind of adversity they had to battle through and all the highs and lows of this day," he said. "The weather, the two-hour halftime and everything we went through as a football team. It's hard enough to come in here and play the tradition and for me a very emotional day to have the opportunity to come back, but to throw everything on top," he said.

He also pointed to former South Florida athletic director Lee Roy Selmon, who is in a Tampa hospital after a stroke.

"It's bittersweet not to have the opportunity to share it with him," Holtz said.

USF's Kayvon Webster returned a fumble return 96 yards for a TD four minutes into the game, taking all the momentum from the Irish. They couldn't recover. The score came after Notre Dame took the opening kickoff and drove smartly to the USF 1.

"You look up and they have had the ball and have driven the length of the field and you look up and you are winning, 7-0," Holtz said. "Kind of a good feeling at that point. It kind of symbolized a little bit of the day."

What followed was a nightmare first half for the Irish that included two fumbles, a holding penalty that nullified a Cierre Wood TD run and then an interception of Dayne Crist by USF's Devekeyan Lattimore in the end zone.

"The first half just a disaster. Period," Wood said.

Maikon Bonani kicked three field goals and the Bulls had a 16-0 halftime lead.

Then things got even stranger.

With the crowd getting restless over Notre Dame's erratic play as the teams left the field for halftime, the storms moved in and officials asked fans to evacuate Notre Dame Stadium. The teams were kept in their locker rooms.

When the Irish finally emerged, they had switched quarterbacks from Crist to Tommy Rees, who led them to four straight victories as the starter at the end of last season. Crist was 7-of-15 for 85 yards.

"We didn't expect to have to make this move, obviously, so it's going to require us to obviously evaluate the quarterback situation and make another decision," Notre Dame coach Brian Kelly said.

"This was a step back for us as it relates to where we thought we were going. We certainly did not believe or think that we would have to make the decision that we made today. "

Right after the second delay late in the fourth quarter Jerrell Young intercepted Rees -- Notre Dame's fifth turnover of the game.

Rees threw an 8-yard TD pass to Michael Floyd to cap a 99-yard drive with 21 seconds left as the Irish closed to 23-20. But USF recovered an onside kick and ran out the clock. Rees went 24-for-34 for 296 yards.

With the delays, the game lasted 5 hours, 59 minutes.

Rees also hit Floyd with a scoring pass in the third quarter and Cierre Wood's 1-yard scoring run with 7:35 left made it 23-13 before the Irish failed to convert a 2-point attempt. Floyd, reinstated to the team last month following his suspension for drunken driving, made 12 catches and became the Irish's career leader in receptions, passing Jeff Samardzija (179). Floyd now has 183.

USF's B.J. Daniels completed 18-of-30 for 128 yards and also carried 12 times for a net of 37.

After a pass interference call in the end zone on Irish defensive back Gary Gray, Daniels threw a 2-yard TD pass to Evan Landi that opened up a 23-7 lead with 11 minutes left, capping a 14-play, 80-yard drive.

The Irish moved from the 20 to the South Florida 1 on the opening drive as Wood went 31 yards with a swing pass from Crist on the game's first scrimmage play and Floyd later grabbed a 26-yarder.

Wood had four carries for 21 yards to get the ball to the 1, but his backup Jonas Gray fumbled near the goal line as USF's Young stripped the ball. Webster picked it up and ran 96 yards down the sideline, a score upheld by video replay.

Bonani hit a 49-yarder to put the Bulls up 10-0 and then USF threatened to pull way ahead. After back-to-back facemask penalties on Notre Dame safety and captain Harrison Smith, the Bulls had a first down at the Irish 5.

But the Irish defense held and when Daniels was stopped on a third down from the 1 for no gain, the Bulls sent in Bonani for a 17-yarder that made it 13-0.

Later in the first half, Riddick fumbled a punt and Victor Marc recovered for USF. Bonani hit again from 36 yards out and the lead was 16-0.

After another Notre Dame series ended with an incomplete pass, Kelly could be seen on the sidelines in an animated discussion with the struggling Crist.

Rees completed a 15-yard pass to Floyd early in the third to put the ball at the 5, but once again the Irish couldn't convert. Rees' pass intended for TJ Jones hit the receiver and deflected in the air, resulting in an interception by South Florida's Michael Lanaris.